PURIFICATION OF THERMOSTABLE β-GALACTOSIDASE FROM ANOXYBACILLUS SP KP1 AND ESTIMATION OF COMBINED EFFECT OF SOME CHEMICALS ON ENZYME ACTIVITY USING SEMIPARAMETRIC ERRORS IN VARIABLES MODEL

The thermostable beta-galactosidase from thermophilic Anoxybacillus sp. KP1 was partially purified by Sephadex G-75 gel permeation chromatography with a fold purification of 14.4 and a yield of 11.8%, respectively. The optimal activity of purified beta-galactosidase was pH 9.0 and a temperature of 60 degrees C. The enzyme was stable at pH 9.0. Thermostability of the enzyme was also 60 degrees C. The molecular weight of the enzyme was determined as 68 kDa by SDS-PAGE. The partially purified thermostable alkaline beta-galactosidase was significantly inhibited by various divalent cations, including Hg2+ and Cu2+ while Ca2+ and Mg2+ ions activated the enzyme activity. The combined effects of some chemicals on beta-galactosidase activity by Anoxybacillus sp. KP1 were studied using semiparametric errors in variables methodology. The optimal combinations of chemicals concen-tration for maximum beta-galactosidase activity was determined as 4 mM DTT, 4 mM PMSF, 4 mM NEM, 4 mM Iod A, 4 mM beta-Mer and 10 mM phen.